Cane growers in Queensland's Mackay region have been slow to expand into macadamia nuts, as an extra source of income, away from the volatile sugar market.

But that's to be expected according to Gray Plantations general manager Kim Wilson, who oversees macadamia orchards in northern New South Wales and Mackay.

The company has 50,000 trees on two Mackay farms and just finished the second 'serious' commercial harvest, as the trees take time to mature.

In 2005 Gray Plantations decided to convert cane land into Macadamia orchards as land was becoming too expensive around the northern NSW region.

Mr Wilson says the recent harvest has been very successful and the trees are living up to expectations, but few farmers in the region have followed the trend, however it's only a matter of time.

"Since we've started to get some harvest off [the trees], we've had several farmers come to us in the last few months enquire a bit more detail about the financial analysis of it, the cost of trees and the yields expected.

"It would be great to see it further grow in this area."

There was the view farmers would diversify into macadamias, but Mr Wilson says it's normal for the growth to take time.

"It's typical based on what I saw in the Bundaberg region when new plantings went in there 20 to 25 years ago."

"It takes a long while for the farmer to accept that perhaps this new crop is worthwhile.

"I think once we can demonstrate three, four, or five years of some good crops coming off the trees, then I think people will start to look at it a bit more seriously," Mr Wilson said.

He says the farms are producing bigger yields as the trees get older and it's sparked the interest of local farmers, particularly in the last year.